1-year Transplant-related Mortality Research Articles

Pediatric adapted risk index to predict 2-year transplant-related mortality post-HSCT in children

AbstractSeveral attempts have been made to optimize pretransplant risk assessment to improve hematopoietic stem cell transplantation (HSCT) decision-making and to predict post-HSCT outcomes. However, the relevance of pretransplant risk assessment to the pediatric population remains unclear. We report the results of revalidation of the hematopoietic cell transplantation comorbidity index (HCT-CI) in 874 children who received 944 HSCTs for malignant or nonmalignant diseases at a single center. After finding the HCT-CI invalid in our patient population, we proposed a modified pediatric adapted scoring system that captures risk factors (RFs) and comorbidities (CoMs) relevant to pediatrics. Each RF/CoM was assigned an integer weight based on its hazard ratio (HR) for transplant-related mortality (TRM): 0 (HR < 1.2), 1 (1.2 ≥ HR < 1.75), 2 (1.75 ≥ HR < 2.5), and 3 (HR ≥ 2.5). Using these weights, the pediatric adapted risk index (PARI) for HSCT was devised, and patients were divided into 4 risk groups (group 1: without RF/CoM; group 2: score 1-2; group 3: score 3-4; and group 4: score ≥5). There was a linear increase in 2-year TRM from group 1 to 4 (TRM, 6.2% in group 1, 50.9% in group 4). PARI was successfully validated on an internal and external cohort of pediatric patients. Comparing models using c-statistics, PARI was found to have better performance than HCT-CI in predicting 2-year TRM in children, with Akaike and Schwarz Bayesian information criteria values of 1069.245 and 1073.269, respectively, using PARI, vs 1223.158 and 1227.051, respectively, using HCT-CI. We believe that PARI will be a valuable tool enabling better counseling and decision-making for pediatric patients with HSCT.

The Clinical Influence of Complete Remission With Incomplete Count Recovery (CRi) on Single-Unit Unrelated Cord Blood Transplantation in Patients With Acute Leukemia

Recent evidence has indicated that measurable residual disease (MRD) markedly affects the prognosis of patients with acute leukemia post-transplantation. However, the prognostic relevance of complete remission with incomplete count recovery (CRi) before transplantation has not been extensively explored. In this single-center, longitudinal study, we assessed the outcomes of 466 MRD-negative acute leukemia patients who underwent single-unit unrelated cord blood transplantation (sUCBT), including 117 patients with CRi. We observed that acute myeloid leukemia (AML) patients with CRi had a significantly lower cumulative incidence of both neutrophil (90.8% versus 96.5%) and platelet engraftment (67.2% versus 85.3%) and experienced increased transplant-related mortality (TRM) (100-day TRM: 14.2% versus 5.3%; 1-year TRM: 20.6% versus 11.3%; P = .024 and .063, respectively), mainly due to infection-related deaths, compared to those in complete remission (CR). Multivariate analysis revealed that CRi was an independent adverse predictor of both neutrophil and platelet engraftment and increased 100-day TRM in AML patients. However, CRi status did not affect relapse or reduce 5-year overall survival (OS), leukemia-free survival (LFS), or GVHD-free relapse-free survival (GRFS) in the AML cohort. Conversely, for patients with acute lymphoblastic leukemia (ALL), CRi did not impact engraftment, TRM, relapse or survival after sUCBT. Our findings underscore that CRi status before sUCBT portends poorer engraftment outcomes and a greater TRM in AML patients, although it does not significantly affect the prognosis of ALL patients.

Haematopoietic stem cell transplantation after reduced intensity conditioning in children and adolescents with chronic myeloid leukaemia: A prospective multicentre trial of the I-BFM Study Group.

This prospective multicentre trial evaluated the safety and the efficacy of a thiotepa/melphalan-based reduced intensity conditioning (RIC) haematopoietic stem cell transplantation (HSCT) in children and adolescents with chronic myeloid leukaemia (CML) in chronic phase (CP). Thirty-two patients were transplanted from matched siblings or matched unrelated donors. In 22 patients, HSCT was performed due to insufficient molecular response or loss of response to first- or second-generation tyrosine kinase inhibitor (TKI), with pretransplant BCR::ABL1 transcripts ranging between 0.001% and 33%. The protocol included a BCR::ABL1-guided intervention with TKI retreatment in the first year and donor lymphocyte infusions (DLI) in the second-year post-transplant. All patients engrafted. The 1-year transplant-related mortality was 3% (confidence interval [CI]: 0%-6%). After a median follow-up of 6.3 years, 5-year overall survival and event-free survival are 97% (CI: 93%-100%) and 91% (CI: 79%-100%) respectively. The current 5-year leukaemia-free survival with BCR::ABL1 <0.01% is 97% (CI: 88%-100%) and the current TKI- and DLI-free survival is 95% (CI: 85%-100%). The incidence of chronic graft-versus-host disease (GvHD) was 32%, being severe in four patients (13%). At last follow-up, 31 patients are GvHD-free and have stopped immunosuppression. RIC HSCT following pretreatment with TKI is feasible and effective in children and adolescents with CP-CML with an excellent disease-free and TKI-free survival.

Single non-blood-related umbilical cord blood transplantation using a reduced-intensity conditioning regimen for the treatment of severe aplastic anemia

Objective: To evaluated the clinical efficacy of a reduced-intensity preconditioning regimen for single non-blood-related umbilical cord blood transplantation (sUCBT) in the treatment of severe aplastic anemia (SAA) . Methods: The clinical data of 63 patients with SAA who underwent sUCBT from January 2021 to July 2023 at the Department of Hematology of the First Affiliated Hospital of USTC were retrospectively analyzed. Fifty-two patients received total body irradiation/total bone marrow irradiation (TMI) combined with fludarabine or a cyclophosphamide- conditioning regimen (non-rATG group) , while 11 patients received rabbit anti-human thymocyte immunoglobulin (rATG) combined with TMI, fludarabine, or the cyclophosphamide-conditioning regimen (rATG group) . All patients received cyclosporine A and mycophenolate mofetil for graft-versus-host disease (GVHD) prophylaxis. Complications post-transplantation and long-term survival were compared between the two groups. Results: The baseline parameters were balanced between the two groups (P>0.05) . In the rATG group, all patients achieved stem cell engraftment, and in the non-rATG group, five patients had primary graft failure. There was no significant difference in the cumulative incidence of neutrophil engraftment at 42 days after transplantation or platelet engraftment at 60 days between the two groups. The incidence of grade Ⅱ-Ⅳ acute GVHD in the rATG group was significantly lower than in the non-rATG group (10.0% vs. 46.2% , P=0.032) , and the differences in the cumulative incidences of grade Ⅲ/Ⅳ acute GVHD and 1-year chronic GVHD were not statistically significant (P=0.367 and P=0.053, respectively) . There were no significant differences in the incidences of pre-engraftment syndrome, bacterial bloodstream infections, cytomegalovirus viremia, or hemorrhagic cystitis between the two groups (P>0.05 for all) . The median follow-up time for surviving patients was 536 (61-993) days, and the 1-year transplantation related mortality (TRM) of all patients after transplantation was 13.0% (95% CI 6.7% -24.3% ) . Among the patients in the non-rATG and rATG groups, 15.5% (95% CI 8.1% -28.6% ) and 0% (P=0.189) , respectively, had mutations. The 1-year overall survival (OS) rate of all patients after transplantation was 87.0% (95% CI 75.7% -93.3% ) . The 1-year OS rates in the rATG group and non-rATG group after transplantation were 100% and 84.5% , respectively (95% CI 71.4% -91.9% ) (P=0.198) . Conclusion: The preliminary results of sUCBT with a low-dose irradiation-based reduced-intensity conditioning regimen with fludarabine/cyclophosphamide for the treatment of patients with SAA showed good efficacy. Early application of low-dose rATG can reduce the incidence of acute GVHD after transplantation without increasing the risk of implantation failure or infection.

Clinical analysis of 14 patients aged ≤ 50 years with high-risk multiple myeloma treated with allogeneic hematopoietic stem cell transplantation

Objective: To evaluate the efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in young patients with high-risk multiple myeloma (HRMM) and analyzed the factors affecting patient prognosis. Methods: In this retrospective study, we analyzed the clinical data of 14 patients with HRMM with cytogenetic abnormalities or high-risk biological factors who underwent allo-HSCT at the Hematopoietic Stem Cell Transplantation Center of the Institute of Hematology & Blood Diseases Hospital between November 2016 and November 2022. Results: There were seven males and seven females included in the study, with a median age of 39.5 (31-50) years at the time of allo-HSCT. The median number of treatment lines before transplantation was 2 (1-6) . Before allo-HSCT, 42.9% (6/14) of the patients did not achieve complete remission, while 35.7% (5/14) of the patients achieved measurable residual disease positivity. After transplantation, all patients were evaluated for their treatment response, and the overall response rate was 100% (14/14) . All 14 patients successfully underwent allo-HSCT, with median engraftment times for neutrophils and platelets of 11 (10-14) days and 13 (9-103) days, respectively. Acute grade Ⅱ-Ⅳ graft-versus-host disease (GVHD) occurred in five patients (35.7%) , and two patients (14.3%) developed moderate-to-severe chronic GVHD. The median follow-up time after allo-HSCT was 18.93 (4.10-72.53) months, with an expected 2-year transplant-related mortality rate of 7.1% (95% CI 0%-21.1%) and an expected 2-year overall survival rate of 92.9% (95% CI 80.3%-100.0%) . Moreover, the expected 1-year and 2-year progression-free survival rates were 92.9% (95% CI 80.3%-100.0%) and 66.0% (95% CI 39.4%-100.0%) , respectively, and the 2-year cumulative incidence of relapse was 28.9% (95% CI 0%-56.7%) . Upfront allo-HSCT following complete remission after induced therapy and the presence of chronic GVHD might be favorable prognostic factors. Conclusion: allo-HSCT is an effective treatment for improving the prognosis of young patients with HRMM.

Venetoclax and Azacytidine Treatment for High Risk Myelodysplastic Syndromes and Chronic Myelomonocytic Leukemia As a Bridge Therapy to Transplant. a GESMD Study

Introduction Allogeneic hematopoietic cell transplantation (alloHCT) is the only potentially curative treatment for myelodysplastic syndromes (MDS) and chronic myelomonocytic leukemia (CMML). Most common approach to bridge higher-risk MDS to alloHCT is to reduce tumor burden before alloHCT with azacytidine (AZA). Currently with this strategy less than 50% of patients achieve overall response rate (ORR) and less than 20% complete response (CR). Moreover, it is associated with a considerable rate of drop outs (approximately 50%) due to progression disease and mortality prior to alloHCT. Therefore, we need more effective treatments with faster and higher responses to facilitate more patients to undergo alloHCT. Venetoclax with AZA (VEN/AZA) is being investigated mostly in unfit MDS patients, it has shown higher ORR and early responses. Recently, a study suggested promising activity in 13 high-risk MDS patients who received VEN/AZA and proceeded to alloHCT (Komrokji et al, BCJ, 2022). The objective of our study is to analyze the feasibility, toxicity, and efficacy of VEN/AZA treatment in MDS and CMML patients who are intended to undergo alloHCT. Methods This is a retrospective multicenter study that includes high-risk MDS and CMML patients treated with VEN/AZA who are intended to undergo alloHCT. The response rate was assessed according to the IWG 2006, IWG 2023, ELN 2022. Savona criteria were used in CMML. Results A total of 23 patients were included, with a median age of 61 years (41-74), including 19 MDS and 4 CMML patients. Eight patients received VEN/AZA in a relapsed/refractory (R/R) setting, while 15 in first line (1L). Most patients received a 14-day scheme of VEN (n=16). The administration of VEN/AZA and other characteristics are described in Table 1. Grade 3/4 cytopenias were frequent (83% neutropenia 65% thrombocytopenia, 59% anemia), 17% experienced febrile neutropenia and 17% required hospitalization. G-CSF was used in 44% of patients, antifungal prophylaxis in 43%, and cycle delays due to cytopenias happened in half of them (47%). Thirty-day mortality was 0%, and one patient (4%) died within the first 60 days due to disease progression. The response rate following IWG 2023 criteria was: 7 CR (30%), 6 CR with limited count recovery (CR L, 26%), 4 CR with partial hematologic recovery (CRh, 17%), 3 partial remissions (PR, 13%), 1 hematologic improvement (HI, 4%), and 2 no response (9%). The ORR was 91.3% (21/23), and the rate of composite complete responses (CRc) including CR, CR L and CRh was 73.9% (17/23) . These responses occurred rapidly, all patients achieved the first response in 1 cycle and the median to best response was 1 cycle (range 1-3). In R/R patients the ORR was 87% and the CRc was 62%. Using the ELN 2022 versus IWG 2023 response criteria results in similar CRc, higher rate of CR (34% vs 22%) and lower ORR (86 vs 91%). The median follow-up since the start of treatment was 13.6 months (95% CI: 5.2-21). The 2-year overall survival (OS) was 63% (95% CI ± 24%). Currently, there are 2 patients awaiting alloHCT. Among the 21 evaluable patients, 19 underwent alloHCT, resulting in a alloHCT rate of 91%. The 2 patients who were not transplanted included one CMML patient with disease progression prior alloHCT and one refractory MDS. AlloHCT was performed with a median of 3 prior cycles (range: 1-9), and the median time from the start of VEN/AZA to transplantation was 4 months (range: 2.5-10). One patient who did not respond to VEN/AZA was treated with chemotherapy prior alloHCT achieving CR. Two patients progressed before alloHCT, one achieved CR after chemotherapy and the other one has received a sequential alloSCT. The two-year post-transplant OS was 67% (95% CI ± 28%) (Figure 1). Four patients relapsed after alloHCT, resulting in a two-year cumulative incidence of relapse (CIR) of 37% (95% CI ± 28%). One of these patients was treated with VEN/AZA post-transplant and he is currently in CR for 1.5 years. 2-year transplant-related mortality was 6% (95% CI ± 12%). Conclusion Treatment with VEN/AZA as a bridge to alloHCT in MDS and CMML patients is feasible with a high rate of patients undergoing alloHCT. It provides high and quick responses, even in R/R patients, with low treatment-related toxicity. Funding This study was supported by grants from the Institute of Health Carlos III (ISCIII), with grant numbers PI19/01476 and PI22/01660, co-financed by the European Union. Additional support was provided by Emili-Letang (HCPB).

Umbilical Cord Blood Stem Cells As Third-Party Adjuvant Infusion in Human Leukocyte Antigen Antibody-Positive Patients Undergoing Allogeneic Hematopoietic Stem Cell Transplantation

Introduction: The presence of human leukocyte antigen (HLA) antibodies, even if not donor-specific antibodies (DSA), is an important risk factor for graft failure (GF) or poor graft function (PGF) in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, there is no ideal strategy for eradicating or descending HLA antibodies in this population. In the present study, we investigated the efficacy and safety of unrelated umbilical cord blood stem cells (CBCs) as a third-party adjuvant infusion in patients with HLA antibodies undergoing allo-HSCT. Methods:Patients undergoing allo-HSCT from July 2017 to June 2021 were enrolled in this study and HLA antibodies were routinely tested before transplantation. Patients were divided into three groups: Group A (patients with positive/weak positive HLA antibodies and with CBCs infusion), Group B (patients with HLA antibodies positive/weak positive without CBCs infusion), and Group C (patients without HLA antibody nor CBCs infusion). Single unrelated CBCs (HLA4/6 or more compatible ) were infused four hours before donor stem cells. The clinical characteristics of the patients and the paired donors were collected. The occurrence of granulocyte and platelet engraftment time, graft-versus-host disease (GVHD), cytomegalovirus (CMV), Epstein-Barr virus (EBV) reactivation, one-year and two-year relapse-free survival (RFS), transplantation-related mortality (TRM), and overall survival (OS) for all three groups of patients were also analyzed in this study. Results:A total of 90 patients were included in this study (17 in group A, 36 in group B, and 37 in group C). The baseline clinical characteristics of the patients were presented in Table 1. No obvious adverse effects were observed in the process of CBCs infusion. All the patients achieved 100% donor chimerism without CBCs engraftment. There were no significant differences in granulocyte and platelet engraftment time between the three groups. Two patients in Group A and C, and 3 patients in Group B developed PGF, respectively. There were no significant differences in the incidence and grades of acute or chronic GVHD among the three groups ( Figure A, B). In the first 3 months after allo-HSCT, the incidence of EBV reactivation was higher in patients in Group B than that in Group A and C, respectively ( Figure C). There were no significant differences in the CMV reactivation between the three groups in the first 3 months after transplantation ( Figure D). Patients in Group A and B both had lower 1-year RFS and higher 1-year TRM, compared with Group C, respectively ( Figure E, F). However, there were no significant statistical differences in 2-year RFS and TRM between the three groups. Although patients in Group A had longer 2-year OS than that in Group B, there were no significant differences between the two groups: Group A vs Group B (76.5% vs 55.6%, P = 0.194), Group B vs Group C (55.6% vs 85.5%, P &amp;lt; 0.05)( Figure G). A multifactorial Cox regression risk model was established to explore the risk factors affecting OS and suggested that patients' pre-transplantation status (with active malignant disease or minimal residual disease positive) and HLA antibodies pre-transplant were the most independent risk factors for OS (HR = 4.380, 95% CI = 1.544-12.427, P&amp;lt;0.05; HR = 0.196, 95% CI = 0.065-0.587, P&amp;lt;0.05). Conclusions: Patients with positive/weak positive HLA antibodies receiving CBCs as a third-party adjunctive infusion were safe, and there was a benefit in the incidence of EBV reactivation compared to such a population without CBCs infusion. The patients with negative HLA antibodies had higher 1-year RFS and lower 1-year TRM than those with positive/weakly positive HLA antibodies regardless CBCs infusion. Due to the small number of included cases, we will expand the sample number to further validate our results in the future.

Optimized Double-Unit Cord Blood Transplantation Mitigates Transplant-Related Mortality Resulting in High Progression-Free Survival in Adults with Hematologic Malignancies

Background : Double-unit cord blood transplantation (dCBT) with intermediate intensity conditioning (Cy50/ Flu150/ Thio10/ TBI400cGy) and cyclosporine-A (CSA)/ mycophenolate mofetil (MMF) graft-versus-host disease (GVHD) prophylaxis has been associated with high progression-free survival (PFS) in adult patients (pts) with hematologic malignancies ( Barker JN et al, Blood Advances 2020). Now, our Center has investigated multiple refinements to further mitigate transplant-related mortality (TRM). Herein, we have analyzed transplant outcomes in these adult dCBT pts to establish an optimized dCBT platform. Methods : Consecutive adult first allograft pts with high-risk hematologic malignancies who underwent first allografts with intermediate intensity dCBT between 3/2018-8/2022 were analyzed. Optimizations involved further refined unit selection placing highest priority on unit quality (i.e. optimized banking practices) &amp; CD34+ cell dose over HLA-match, ensuring therapeutic (CSA) levels (&amp;gt; 250 ng/mL) by day 0, prompt treatment of pre-engraftment syndrome (PES) &amp; letermovir prophylaxis in CMV seropositive pts from day +7. Also, we have investigated 2 strategies to mitigate acute graft-versus-host disease (aGVHD): pts early in the study period received CSA, MMF &amp; tocilizumab (8 mg/kg on day -1) prophylaxis ( Toci Group), whereas recent pts ( Recent Group) received CSA/ MMF with prompt therapy of clinically diagnosed aGVHD. Results : Of 74 patients (Table), 49 were in the Toci Group, &amp; 25 in the Recent Group. Most pts were transplanted for acute leukemia (n = 55, 74%) &amp; over half (n = 39, 53%) had non-European ancestry. Distribution of diagnoses, CMV serostatus, HCT-CI &amp; graft characteristics were similar between the groups but Recent Group pts tended to be younger (38 vs. 47 years, p = 0.071). Toci Group pts had delayed neutrophil recovery [engraftment incidence 94% (95%CI: 87-99) at a median of 25 days (range 16-40), one graft failure], but low rates of PES (n = 19, 39%). The day-100 incidence of grade II-IV &amp; III-IV aGVHD were 69% (95%CI: 56-82) &amp; 10% (95%CI: 2-19), respectively. One pt (false negative CMV-serostatus) who did not receive letermovir had CMV infection. One-year TRM was 16% (95%CI: 6-27) with a 1-year relapse rate of 6% (95%CI: 3-13). TRM was due to infection (n = 3), aGVHD (n = 3, 1 with concurrent COVID-19 infection), multiorgan failure (n = 2) &amp; graft failure (n = 1). With a median follow-up of 47 months (range 28-62), the 1-year OS was 84% (95%CI: 73-94) &amp; 1-year PFS was 78% (95%CI: 66-89). By contrast, the engraftment incidence in Recent Group pts was 100% with a faster median neutrophil recovery of 19 days (range 11-36, p = 0.002) &amp; all engrafted platelets at a median of 36 days (range 24-92). However, most Recent group pts developed PES [n = 20 (80%), p &amp;lt; 0.001] although this responded promptly to short course corticosteroids. Day 100 grade II-IV aGVHD was also higher [92% (95%CI: 81-99), p = 0.009], although grade III-IV aGVHD was low [8% (95%CI: &amp;lt;1-19)] &amp; similar to tocilizumab pts. Day 100 incidence of CMV was 0%. With a median follow-up of 17 months (range 6-50), the 1-year TRM in Recent Group pts is 0% with a 1-year relapse incidence of 13% (95%CI: 7-27). Consequently, the 1-year OS &amp; PFS are high at 96% (95%: 89-99) &amp; 87% (95%CI: 74-99), respectively (Figure). Conclusions: Optimized dCBT with intermediate intensity conditioning, graft selection that prioritizes unit quality &amp; CD34+ dose, CSA/ MMF prophylaxis with prompt therapy of PES &amp; aGVHD, &amp; letermovir CMV prophylaxis mitigates TRM in young &amp; middle-aged adults. Thus, combined with relatively low relapse rates, the PFS &amp; OS are high. Tocilizumab has been abandoned due to its notable association with delayed neutrophil engraftment &amp; lack of survival advantage. Letermovir is highly effective completely preventing CMV infections &amp; may contribute to the reduced aGVHD-related mortality recently (as compared to the pre-tocilizumab era), since avoidance of CMV antiviral therapy toxicities greatly facilitates aGVHD prevention &amp; therapy. Given the rapid availability of cryopreserved unmanipulated CB grafts &amp; frequent limitations of URD availability for minority populations, optimized dCBT is a highly attractive curative therapy for acute leukemias &amp; other high-risk myeloid malignancies warranting prospective multi-center investigation.

Weight loss post-allogeneic stem cell transplant is associated with increased transplant-related mortality.

Allogeneic stem cell transplant (allo-HSCT) patients are at risk of malnutrition and weight loss from impaired oral intake resulting from gastrointestinal toxicities, dysgeusia, and psychological effects. A retrospective review of 264 adult patients transplanted at Princess Margaret Cancer Centre who achieved relapse-free survival up to 3months after allo-HSCT was performed. Overall incidence of patients who experienced WL (WL) ≥ 10% from HSCT to 3-month post-transplant was 45.9% and from HSCT to 6months was 56.6%. Patients with ≥ 10% WL from allo-HSCT at 3months and 6months had similar 2-year overall survival (OS) compared to those with < 10% WL, 55.7% vs 62.8% (HR = 1.38, p = 0.11) and 71.1% vs 77.2% (HR = 1.37, p = 0.27), respectively. Patients with ≥ 10% WL 3 and 6months from allo-HSCT also had similar 2-year relapse-free survival (RFS) compared to those with < 10% WL, 48.1% vs 55.8% (HR = 1.26, p = 0.22), and 62.7% vs 69.8% (HR = 1.29, p = 0.31), respectively. The 2-year transplant-related mortality (TRM) was higher for those with ≥ 10% WL from allo-HSCT to 3months, 35.4% vs 16.9% (HR = 2.39, p = 0.0007) and 6months, 22% vs 8% (HR = 3.1, p = 0.0034). Although statistical significance was not observed for OS or RFS, patients who experienced ≥ 10% WL 3- and 6-months post allo-HSCT experienced higher 2-year TRM. These results highlight the importance of early intervention and close monitoring of weight post allo-HSCT. Approaches to WL post allo-HSCT should be multifaceted and include members of the interdisciplinary team in order to decrease TRM.

Efficacy and safety of allogeneic hematopoietic stem cell transplantation in the treatment of 28 patients with hepatitis-related aplastic anemia

Objective: To evaluate the efficacy and safety of HLA-haploidentical hematopoietic stem cell transplantation (allo-HSCT) for hepatitis-related aplastic anemia (HRAA) patients. Methods: Retrospective analysis was performed on hepatitis-associated aplastic anemia patients who received haplo-HSCT at our center between January 2012 and June 2022. October 30, 2022 was the final date of follow-up. Results: This study included 28 HRAA patients receiving allo-HSCT, including 18 males (64.3% ) and 10 females (35.7% ), with a median age of 25.5 (9-44) years. About 17 cases of severe aplastic anemia (SAA), 10 cases of very severe aplastic anemia (VSAA), and 1 case of transfusion-dependent aplastic anemia (TD-NSAA) were identified. Among 28 patients, 15 patients received haplo-HSCT, and 13 received MSD-HSCT. The 2-year overall survival (OS) rate, the 2-year failure-free survival (FFS) rate, the 2-year transplant-related mortality (TRM) rate, the 100-day grade Ⅱ-Ⅳ acute graft-versus-host disease (aGVHD) cumulative incidence rate, and the 2-year chronic graft-versus-host disease (cGVHD) cumulative incidence rate were 81.4%, 81.4% (95% CI 10.5% -20.6% ), 14.6% (95% CI 5.7% -34.3% ), 25.0% (95% CI 12.8% -45.4% ), and 4.2% (95% CI 0.6% -25.4% ), respectively. After transplantation, all patients had no significant liver function damage. Compared with the MSD-HSCT group, only the incidence of cytomegaloviremia was significantly higher in the haplo-HSCT group [60.0% (95% CI 35.2% -84.8% ) vs 7.7% (95% CI 0-22.2% ), P=0.004]. No statistically significant difference in the Epstein-Barr virus was found in the 2-year OS, 2-year FFS, 2-year TRM, and 100-day grade Ⅱ-Ⅳ aGVHD cumulative incidence rates and 2-year cGVHD cumulative incidence rate. Conclusion: Allo-HSCT is safe and effective for HRAA, and haplo-HSCT can be used as a safe and effective alternative for newly diagnosed HRAA patients who cannot obtain HLA-matched sibling donors.

Impact of Iron Overload and Iron Chelation with Deferasirox on Outcomes of Patients with Severe Aplastic Anemia after Allogeneic Hematopoietic Stem Cell Transplantation

Patients suffering from severe aplastic anemia (SAA) need frequent blood transfusions during allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, these transfusions can result in an excess of iron in the body tissues, which can negatively impact the success of transplantation. This study aimed to examine the impact of pretransplantation iron overload (IO) on the outcomes of allo-HSCT in patients with SAA. It also investigated whether iron chelation (IC) therapy is necessary to enhance transplantation outcomes in SAA patients by providing guidelines for determining when excess iron should be chelated. The study consisted of 2 parts. In cohort 1, which was retrospective and conducted from April 2012 to December 2018, SAA patients receiving their first allo-HSCT were divided into 2 groups based on their pretransplantation serum ferritin (SF) level: the IO group (SF >1000 ng/mL; n=17) and the non-IO group (SF ≤1000 ng/mL; n=48). Cohort 2, a prospective clinical trial conducted from January 2019 to July 2020, included SAA patients diagnosed with IO who were treated with IC therapy using deferasirox at a dose of 10 to 30 mg/kg. Patients were separated into 2 groups based on their pretransplantation SF level: the IC success (ICsuccess) group (SF ≤1000 ng/mL; n=18) and the IC failure (ICfailure) group (SF >1000 ng/mL; n=28). All participants were evaluated for the correlation between pretransplantation SF level and transplantation outcomes. A P value <.05 was considered statistically significant. There was no significant difference in the speed of engraftment among the 3 cell lineages or in the incidence of 100-day grade II-IV acute graft-versus-host disease (aGVHD), grade III-IV aGVHD, or 3-year chronic GVHD between the 2 groups in both cohorts. Of note, however, in cohort 1, both 1-year overall survival (OS) (41.2% versus 83.3%; P < .001) and 3-year OS (35.3% versus 83.3%; P < .001) were significantly worse in the IO group. Furthermore, 180-day transplantation related mortality (TRM) (47.1% versus 14.6%; P=.005) and 1-year TRM (52.9% versus 16.7%; P=.002) were significantly higher in the IO group. The IO group was significantly associated with inferior 3-year OS in both univariate and multivariate analyses. In cohort 2, 1-year OS (88.9% versus 42.9%; P=.003) and 3-year OS (83.3% versus 42.9%; P=.007) were significantly better in the ICsuccess group, whereas 180-day TRM (11.1% versus 39.3%; P=.040) and 1-year TRM (11.1% versus 57.1%; P=.003) were significantly lower in the ICsuccess group. These differences were confirmed in both univariate and multivariate analyses. This study involving 2 cohorts shows that pre-HSCT IO has a negative impact on transplantation outcomes in SAA patients. Chelating excess iron with an SF level <1000 ng/mL was found to be necessary and could potentially improve the outcomes.

Comparison of clinical outcomes between peripheral blood stem cells and peripheral blood stem cells plus bone marrow in myelodysplastic syndrome patients with haploidentical transplantation.

The comparison of haploidentical G-CSF-mobilized peripheral blood and bone marrow transplantation (HBMT) for patients with myelodysplastic syndrome (MDS) and haploidentical G-CSF-primed peripheral blood stem cell transplantation (HPBSCT) remains unclear. We performed a retrospective analysis using a propensity score method on 140 MDS patients who received HPBSCT (n = 46) or HBMT (n = 94) with BU/CY as a conditioning regimen prior to transplantation at our center between June 2016 and June 2021. HBMT recipients were associated with a reduced incidence of grade III-IV acute GVHD (17.22% vs. 30.57%, p = 0.019) within 100 days, reduced 2-year transplant-related mortality (TRM) (14.29% vs. 28.94%, p = 0.045) and superior 2-year overall survival (OS) (81.6% vs. 66.0%, p = 0.027), progression-free survival (PFS) (80.9% vs. 61.2%, p = 0.015), and GVHD relapse-free survival (GRFS) (64.6% vs. 53.3%, p = 0.062) compared with HPBSCT, but 2-year relapse incidence (RI) (5.96% vs. 9.39%, p = 0.445) was not affected. Multivariate analysis revealed that a GPB/GBM mixture was the independent factor for a reduced incidence of grade III-IV acute GVHD (p = 0.018) and TRM (p = 0.048), improved OS (p = 0.029), PFS (p = 0.019) and GRFS (p = 0.072). Collectively, the use of a GPB/GBM mixture as stem cell grafts for haplo-HSCT in patients with MDS appears to be an optimal choice.

The impact of transportation time on apoptosis in allogeneic stem cell grafts and the clinical outcome in malignant patients with unrelated donors

BackgroundThe quality of cells in peripheral blood stem cell (PBSC) grafts is important for allogeneic stem cell transplantation outcome. The viability of PBSC grafts may decrease during transportation time between donor and transplant center. We hypothesize that the graft viability based on apoptosis and necrosis in the graft may better reflect graft quality and clinical outcome. MethodsPBSC graft viability from unrelated donors was analyzed in 91 patients. Viable cells were defined as 7-aminoactinomycin D– and Annexin V–negative. The clinical outcome, including survival, transplant-related mortality and graft-versus-host disease (GvHD), was correlated to graft viability. ResultsGrafts transported for 1 day had a median viability of 86.4% (range 63.8 to 98.9%), and grafts transported for 2 days had median viability of 83.2% (range 52.8% to 96.2%) (P = .003). Grafts were divided into two groups based on the median graft viability of 85.1%. Patients who received low viability grafts had lower 1-year survival of 63.7% compared with 88.9% for those who received high viability grafts (P = .007). In the multivariate analysis, transplant-related mortality (TRM) was higher in the low viability group (P = .03), whereas overall survival was not significantly associated with graft viability. The incidence of acute GvHD grade II to IV, chronic GvHD and relapse risk remained comparable between the groups. ConclusionLow graft viability was an independent predictor of 1-year survival and TRM after adjusting for multiple confounders. Better graft quality markers are important for the detection of clinically important variations in the stem cell graft.

Updated Outcomes during the Pandemic: Relationship between CD34and CD3 Cell Doses, One-Year Graft-Versus-Relapse-Free-Survival, Graft-Versus-Host Disease, and Overall Survival in Haploidentical Hematopoietic Stem Cell Transplantation Using Post Transplant Cytoxan: A Single Center Experience

Background:Haploidentical hematopoietic cell transplantation (haplo-HCT) has emerged as a popular alternative to traditional HLA-matched hematopoietic cell transplant. The major advancement of haplo-HCT has increased donor availability to many patients in need, therefore investigating the factors that may affect outcomes is necessary to improve overall survival and reduce transplant-related mortality. Data regarding optimal dose of CD34 cells, CD3 cells and CD34/CD3 ratio used during haplo-HCT to ensure favorable outcomes with post-transplant cyclophosphamide (PTCy) is lacking. Previously we have reported improved outcomes using CD34 cells limited to 7x10^6 cells/kg or less. In this report we are presenting an updated analysis including outcomes related to CD34/CD3 ratio used during haplo-HCT.Methods:We retrospectively analyzed adult patients at USC Norris Cancer Hospital who received haplo-HCT from 2014 to 2020. The primary endpoint assessed was 1-year GVHD-free/relapse-free survival (GRFS). Secondary endpoints included overall survival (OS), 1-year transplant related mortality (TRM) and incidence of acute and chronic GVHD. Kaplan Meier survival curves and log-rank tests were used to evaluate 1-year GRFS and OS with CD34 cell dose ≥ 7x10^6 cells/kg and < 7x10^6 cells/kg; CD3 cell dose < 2.5x10^8 cells/kg and ≥ 2.5x10^8 cells/kg; and CD34/CD3 ratio <2, 2-3, >3-5 and >5.Results:103 adult haplo-HCT recipients were reviewed with 55.3% male and 44.7% female. The age range was 21-71 years old (median = 51), and a majority of patients were Hispanic (62%). The most common underlying hematologic disorders included AML (40.8%), ALL (34.1%), and MDS/MPN (13.6 %). 41.7% patients with leukemia were in CR1, 55% were CR2/CR3 and 78% were MRD negative by flow cytometry prior to transplant. 73% received myeloablative conditioning and 83.5% received peripheral blood stem cells.Median CD34 dose, CD3 dose and CD34/CD3 ratio were 6.1 x10^6cells/kg, 2.27 x10^8 cells/kg and 3.2 respectively. Median time to recovery of neutrophil, platelets, and lymphocyte was 17, 24, and 124 days respectively. Incidence of 1-year GRFS was 43.7%. 1-year TRM was 13.6% and rate of aGVHD and cGVHD was 42.7% (n = 44) and 35.9% (n = 37) respectively.There was no difference in 1-year GRFS and OS when multiple dose levels of CD34 cells and CD3 cells were compared. Although when dichotomized, a CD34 cell dose of ≥ 7x10^6 cells/kg compared to < 7x10^6 cells/kg showed higher dose had significant improvement in 1- year overall survival (p-value=0.01) but no statistical difference in 1 year GRFS (p value=0.24).CD3 cell dose < 2.5 x 10^8 cells/kg trended towards worse 1-Year GRFS compared to ≥ 2.5 x 10^8 cells/kg (43.9% compared to 58.6%; p-value 0.075), similarly CD3 dose of < 2.5x10^8 cells/kg showed a lower 1-year OS compared to > 2.5x10^8 cells/kg but was not statistically significant (78.7% compared to 89.4%; p-value 0.092). 1-year GRFS and OS did not show statistical difference at CD34:CD3 ratios of < 2, 2-3, 3-5 and > 5, although on cox regression analysis the HR for 1-year GRFS was 2.92 (95% CI 1.21-7.05) in patients with CD34:CD3 > 5 as compared to reference of < 2 (p-value 0.017). Multivariate regression also showed CD3 cell doses of 2-3x10^8 cells/kg and >3 x 10^8 cells/kg were associated with worse 1-year GRFS with HR of 0.43 and 0.40 and p-value of 0.041 and 0.048 respectively when compared to reference of < 1x10^8 CD3 cells/kg.Discussion:Our results demonstrate 43.7% survived 1 year compared with reports of 24-35%. The OS was significantly better in the CD34 dose > 7x10^6 cells/kg. CD3 <2.5x10^8 cells/kg showed a trend towards lower 1-year GRFS and OS, which was not statistically significant. On multivariate analysis CD3 dose of > 2x10^8 cells/kg was associated with inferior 1-year GRFS. Conversely, higher CD34/CD3 ratio >5 was associated with increased 1-year GRFS. Thus, our findings indicate that along with improvement in OS by using >7x10^6 CD34 cells/kg, lower CD 3 cell dose <2x10^8 cells/kg and higher CD34/CD3 ratio > 5 can improve 1-year GRFS in patients receiving haplo-HCT. [Display omitted] DisclosuresChaudhary: Angeles Therapeutics: Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company, Membership on an entity's Board of Directors or advisory committees, Other: Founder, Patents & Royalties: Cell therapy ; Athelas: Consultancy, Current holder of stock options in a privately-held company; Oncotartis: Consultancy; Pancella: Consultancy; Moderna: Current equity holder in publicly-traded company; Celldex: Current equity holder in publicly-traded company; TCR2: Current equity holder in publicly-traded company; Allogene: Current equity holder in publicly-traded company. Yaghmour: Jazz: Consultancy, Honoraria; Astellas: Consultancy; Takeda: Consultancy; Incyte: Consultancy.

Ruxolitinib for chronic steroid-refractory graft versus host disease: a single center experience

BackgroundChronic Graft versus Host Disease (GvHD) is a serious complication of allogeneic hematopoietic stem cell transplant that severely impacts quality of life and long-term survival. About 50-to-60 % of patients treated with steroids require a further line of therapy due to lack of sustained response. Ruxolitinib, a JAK1/2 inhibitor, has recently been approved for the treatment of acute GvHD. MethodsWe aimed to retrospectively evaluate ruxolitinib efficacy and safety in a cohort of patients diagnosed with moderate (25 %) or severe (75 %) steroid-refractory or steroid-dependent chronic GvHD. Response evaluation was performed at three and six months. ResultsThirty-six patients received ruxolitinib after a median of three previous lines (range, r 1–11) for a median of 8.6 months (r 1–51.6). Cutaneous GvHD was the most frequent presentation. We observed an overall response of 59 % (CR 9%, PR 50 %) at three months and 62 % (CR 15 %, PR 46 %) at six months. Two patients had hematologic disease recurrence and were censored at relapse; no other permanent discontinuation due to adverse events were documented. Cutaneous, oral, genital and ocular GvHD significantly improved after treatment. 2-year overall survival and 2-year transplant related mortality were 74 % and 19 % respectively. Ruxolitinib was associated with a significant reduction of steroid dose. ConclusionRuxolitinib was confirmed to be a safe and effective option as salvage treatment also for advanced stages of chronic GvHD. Longer follow up is needed to evaluate durability of response. Prospective analyses on larger cohorts are ongoing.

Factors Associated With Outcome After Cord Blood Transplantation in Children With Acute Leukemia

AbstractWe have analyzed factors influencing the outcome of 102 children with acute leukemia given a cord blood transplantation (CBT) and reported to the Eurocord Registry. Seventy patients with acute lymphoblastic and 32 with acute myeloid leukemia were given either a related (n = 42) or an unrelated (n = 60) CBT. Children given CBT during first or second complete remission were considered as belonging to the good-risk group (n = 66), whereas those who received a transplant in a more advanced stage of disease were assigned to the poor-risk group (n = 36). In the related group (RCBT), 12 of 42 patients received transplantation from an HLA-disparate donor, whereas in the unrelated group (UCBT) 54 of 60 received an HLA mismatched CBT. Kaplan-Meier estimates for neutrophil recovery at day 60 were 84% ± 7% in RCBT and 79 ± 6% in UCBT (P = .16). In multivariate analysis, the most important factor influencing neutrophil engraftment in UCBT was a nucleated cell dose infused greater than 3.7 × 107/kg (P = .05, relative risk [RR] of 1.85, 95% confidence interval [CI]: 0.98-3.4). The incidence of grade II through IV acute graft-versus-host disease was 41% ± 8% in the RCBT group and 37% ± 6% in the UCBT group (P = .59). Kaplan-Meier estimates of 2-year event-free survival (EFS) after RCBT or UCBT were 39% ± 8% and 30% ± 7%, respectively (P = .19). In multivariate analysis, the most important factor influencing EFS was disease status at time of transplantation: good-risk patients had a 2-year EFS of 49% ± 7% as compared to 8% ± 5% in patients with more advanced disease (P = .0003, RR: 0.40, 95% CI: 0.24 to 0.65). This was a consequence of both an increased 1-year transplant related mortality and a higher 2-year relapse rate in the poor-risk group (65% ± 9% and 77% ± 14%, respectively), as compared with good risk patients (34% ± 6% and 31% ± 9%, respectively). These data confirm that allogeneic CBT from either a related or an unrelated donor is a feasible procedure able to cure a significant proportion of children with acute leukemia, especially if transplanted in a favorable phase of disease.

Cyclosporin A and short-term methotrexate versus cyclosporin A as graft versus host disease prophylaxis in patients with severe aplastic anemia given allogeneic bone marrow transplantation from an HLA-identical sibling: results of a GITMO/EBMT randomized trial

AbstractA randomized trial was carried out comparing cyclosporin A (CsA) and short-term methotrexate (MTX) versus CsA alone for graft versus host disease (GVHD) prophylaxis in patients with severe aplastic anemia (SAA) undergoing allogeneic bone marrow transplantation (BMT) from a compatible sibling. Seventy-one patients (median age, 19 years; range, 4-46 years) were randomized to receive either CsA and MTX or CsA alone for the first 3 weeks after BMT. Subsequently, both groups received CsA orally, with gradual drug reduction until discontinuation 8 to 12 months after BMT. Patients randomized in both arms had comparable characteristics and received the same preparative regimen (ie, cyclophosphamide 200 mg/kg over 4 days). The median time for neutrophil engraftment was 17 days (range, 11-31 days) and 12 days (range, 4-45 days) for patients in the CsA/MTX group and the CsA alone group, respectively (P = .01). No significant difference was observed in the probability of either grade 2, grade 3, or grade 4 acute GVHD or chronic GVHD developing in the 2 groups. The Kaplan-Meier estimates of 1-year transplantation-related mortality rates for patients given either CsA/MTX or CsA alone were 3% and 15%, respectively (P = .07). With a median follow-up of 48 months from BMT, the 5-year survival probability is 94% for patients in the CsA/MTX group and 78% for those in the CsA alone group (P = .05). These data indicate that the use of CsA with MTX is associated with improved survival in patients with SAA who receive transplants from compatible siblings.

Real-World Experience Using Letermovir for CMV Prophylaxis in High-Risk Allogeneic Hematopoietic Stem Cell Patients in the Setting of Using T-Cell Depletion As Gvhd Prophylaxis and the Impact on CMV Reactivation, 1-Year Overall Survival, and 1-Year Gvhd-Free-Relapse-Free Survival

Background: Cytomegalovirus (CMV) is a major cause of morbidity in allogeneic hematopoietic stem cell transplant (HSCT) patients. Marty et al. 2017 showed that letermovir is effective in preventing CMV reactivation in high-risk HSCT patients, though only 16% were haplo-identical. Recently, Karam et al. 2019 showed decreased rates of CMV reactivation in haplo-identical HSCT using letermovir in unselected high-risk patients. The effects of letermovir on other transplant-related outcomes including overall survival (OS), relapse free survival (RFS), and Graft-versus-host-disease (GVHD)-free-/relapse-free survival (GRFS), however, are not as well-known. With the increased use of post-transplant cyclophosphamide (PTCy) as GVHD prophylaxis in all transplant types, letermovir use may need to be broadened as those that are T-cell depleted are also at increased risk of CMV reactivation. Methods: We retrospectively analyzed adult patients at USC Norris Cancer Hospital (age ≥ 18) who received allo-HSCT from 2018 to 2020. Recipients who were CMV positive, received T-cell depleting therapies such as PTCy for GVHD prophylaxis and/or ATG in the conditioning regimen, and those who fulfilled the criteria in Marty et al. 2017 were categorized as high-risk. Patients were considered to have CMV reactivation if they had clinically significant serum CMV viremia or organ involvement by day+100. Letermovir was initiated on day+21 for high-risk patients. The primary end-point assessed was day+100 CMV reactivation. Secondary end-points included 1-year OS, 1-year RFS, 1-year transplant-related mortality (TRM), and 1-year GRFS, defined as grade 3-4 acute GVHD, systemic therapy-requiring chronic GVHD, relapse, or death in the 1-year post-HSCT period. Results: A total of 116 adult HSCT recipients were reviewed. 51% were male and 49% were female. The donor sources comprised of 27% match related, 28% match-unrelated, and 49% haplo-identical. Most common diseases included AML (38%), ALL (38%) and MDS (8%). 64% received myeloablative conditioning regimens while 36% received reduced intensity regimens. Furthermore, 92% of patients received peripheral blood with 8% receiving bone marrow. 70% of patients at time of transplant were in CR1 or had stable disease. 61% of patients received letermovir prophylaxis (n=71), all high-risk, and 39% did not (n=45). 13 high-risk patients did not receive letermovir due to insurance limitations and were included in the non-letermovir group. 85% (n =60) received T-cell depleting therapies in the letermovir group compared to 51% (n=23). 90% (n=64) were CMV positive in the letermovir group and 64% (n= 29) were positive in the non-letermovir group. Both groups were similar in regard to the incidence of GVHD. The only factors significantly associated with CMV reactivation were haplo-HSCT, CMV recipient positivity, use of PTCy as GVHD prophylaxis and/or ATG in conditioning regimen, risk status, and GVHD (p = 0.054, p = .017, p = 0.003, p = 0.050, and p = 0.024 respectively). In a subset analysis of all high-risk patients, CMV reactivation was 32% in the letermovir group and 69% in the non-letermovir group (p = 0.03). All other factors were not significantly associated with outcomes. CMV reactivation in the letermovir group was (32%) compared to the non-letermovir group (29%). 1-year OS, 1-year TRM, 1-year RFS, and 1-year GRFS were 85%, 13.2%, 87%, and 60% respectively in the letermovir group compared with 88%, 10%, 90%, and 56% in the non-letermovir group, though not statistically significant. Discussion: Our study confirms improved CMV reactivation outcomes with use of letermovir in high-risk patients. Furthermore, all end-points were similar between both groups, despite increased usage of myeloablative conditioning overall and more high-risk patients in the letermovir group, indicating improved 1-year OS, TRM, and GRFS compared with historical outcomes. Although the primary and secondary end-points were not statistically significant, it may be clinically meaningful, as our center has demonstrated similar outcomes amongst those who were high-risk and received letermovir and those who were low-risk and did not. This suggests broadened use of letermovir may be needed in the prevention of CMV reactivation and the improvement in overall outcomes. Further studies using letermovir in low risk patients may be necessary to investigate improved outcomes in the allo-HSCT setting. Disclosures Yaghmour: Jazz: Consultancy, Speakers Bureau; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Agios: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astellas: Consultancy, Speakers Bureau; Alexion: Consultancy, Speakers Bureau.

Evaluating Gvhd Outcomes Using Post-Transplant Cyclophosphamide/Tacrolimus/Mycophenolate Mofetil As Gvhd Prophylaxis Compared with Methotrexate/Tacrolimus in Matched-Related and Matched-Unrelated Hematopoietic Stem Cell Transplant in Relation to the Haplo-Identical Setting: A Single Center Experience

Background: The use of post-transplant cyclophosphamide (PTCy)/tacrolimus/mycophenolate mofetil (MMF) for GVHD prophylaxis has improved outcomes in haploidentical hematopoietic cell transplantation (haplo-HCT). PTCy is now being evaluated in matched-related (MRD) and matched-unrelated (MUD) allo-HCT. Previous studies demonstrated improved GVHD-free/relapse-free survival (GRFS) when PTCy was combined with two immunosuppressive agents and PTCy has also been associated with better relapse-free survival (RFS) as demonstrated in De Jong et al 2019, though only one immunosuppressive agent was used. Currently, there is limited published data comparing outcomes using PTCy/tacrolimus/MMF to standard MRD/MUD GVHD prophylaxis of methotrexate (MTX)/tacrolimus. The importance of studying this comparison may help to improve GVHD outcomes in MRD and MUD allo-HCT. Methods: We retrospectively analyzed adult patients at USC Norris Cancer Hospital (age ≥ 19) who received allo-HCT from 2018 to 2020. The primary end-points assessed were incidence and severity of 1-year aGVHD and cGVHD. Secondary end-points included day+100 mortality, 1-year overall survival (OS), 1-year RFS, 1-year transplant-related mortality (TRM), and 1-year GRFS, defined as grade 3-4 acute GVHD, systemic therapy-requiring chronic GVHD, relapse, or death in the 1-year post-HCT period. Results: A total of 65 adult MRD and MUD allo-HCT recipients and 53 haplo-HCT patients were reviewed. Of the MRD/MUD patients evaluated, approximately 51% (n = 33) were female and 49% (n = 32) were male. The age range was 20-69 years old (median = 46), and the most common diseases included ALL (46%), AML (31%), MDS (11%), and others (i.e. lymphoma, aplastic anemia (AA), myelofibrosis) (12%). 34% (n = 22) of patients received PTCy on D+3 and D+4 with tacrolimus/MMF/ on D+5 as GVHD prophylaxis and 66% (n = 43) of patients received MTX/tacrolimus on D+1, +3, +6, and +11 as GVHD prophylaxis. All haplo-HCT patients received standard PTCy/tacrolimus/MMF. Stem cell source was primarily PBSC except in HLH and AA patients. The PTCy group had more MUD allo-HCT (64%), degree of antigen mismatch (56%), and median age of 50.5 years compared with the MTX group at 44%, 47%, and 44 years respectively. 70% in the MTX group received MAC compared with 45% in the PTCy group. The haplo group had similar demographics to the MTX group. The mean CD34 cell doses in the PTCy, MTX, and haplo groups were 4.87, 5.36, and 7.24x106 cells/kg respectively. Incidences of total GVHD, aGVHD, and aGVHD grade 3 or 4 in the PTCy group were 55%, 50%, and 4.5% respectively compared with 65%, 35%, and 7% in the MTX group, though not significant. The haplo group had 68%, 55%, and 1.9% respectively. Incidence of total cGVHD and cGVHD requiring systemic therapy in the PTCy group was 4.5% and 0% respectively compared with 30% (p = .02) and 23% (p =.01). The haplo group had 13% and 1.9% respectively. Day+100 mortality, 1-year OS, 1-year RFS, 1-year TRM, and 1-year GRFS in the PTCy group were 0%, 80%, 60%, 0%, and 64% respectively compared with 7%, 88%, 90%, 7.3%, and 59%. The haplo group had 3.8%, 86%, 89%, 14%, and 66%. In a univariate analysis, factors significantly associated with GVHD were disease status (p = .0.12) and CD34 dose (p = 0.015) and antigen mismatch (p = 0.04) was associated with increased mortality. Discussion: Our results demonstrate improved overall and extensive cGVHD outcomes in the PTCy group and thus an improvement in 1-year GRFS. Furthermore, incidence and severity of 1-year cGVHD in this group are improved when compared with previously reported outcomes. 1-year GRFS reported in De Jong et al 2019 was 45% and 1-year GRFS reported for all groups in our study is higher at 66%, 64%, and 59% for the haplo, PTCy, and MTX groups respectively. Although this was not significant, it may be clinically meaningful given the significant improvement in extensive GVHD and improvement in all other secondary end-points except 1-year OS and RFS. Furthermore, the PTCy group had a higher percentage of mismatched antigens yet demonstrated superior outcomes. 1-year OS and RFS were superior in the MTX group however this is likely due to sample size differences. The improved extensive cGVHD and GRFS outcomes observed using PTCy/tacrolimus/MMF in the MRD/MUD setting should continue to be evaluated and currently there is an ongoing prospective, randomized study to further investigate. Disclosures Yaghmour: Jazz: Consultancy, Speakers Bureau; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astellas: Consultancy, Speakers Bureau; Alexion: Consultancy, Speakers Bureau; Agios: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Risk factors and survival analysis for central nervous system complications after allogeneic hematopoietic stem cell transplantation.

To investigate the risk factors as well as their impact on patients' survival of central nervous system (CNS) complications following allogeneic hematopoietic stem cell transplantation (HSCT). All relevant clinical data from a total of 323 patients, who underwent allogeneic HSCT in Xiangya Hospital of Central South University from September 2016 to September 2019, were retrospectively reviewed in this study. The complications' occurrence time, common symptoms and some other clinical data of the patients who developed CNS complications were analyzed descriptively. The risk factors for CNS complications following allogeneic HSCT were analyzed through univariate and multivariate analysis. And the survival analysis was conducted as well. Among the 323 patients who underwent allogeneic HSCT, 32 patients developed CNS complications. These complications occurred in these patients at a median of 32 (range from -1 to 584) d after transplantation. Common symptoms were disturbance of consciousness (78.1%), convulsion (59.4%), and headache (12.5%). Univariate analysis showed that there were significant differences in neutrophil engraftment, platelet (PLT) engraftment, serum cytomegalovirus (CMV) DNA positive, combined with acute graft-versus-host disease (aGVHD), donor selection (P=0.011, P<0.001, P=0.006, P<0.001 or P=0.035, respectively). Multivariate analysis showed that the delay or the failure of PLT engraftment (P<0.001) and combined with aGVHD (P<0.001) were the risk factors for CNS complications. Survival analysis showed that the 1-year overall survival rate (OS) and 2-year OS were significantly lower in patients who developed CNS complications than in the non-CNS complication group (55%±9% vs 89%±2%, 37%±11% vs 85%±3%; both P<0.001). The 1-year disease-free survival rate (DFS) and 2-year DFS were significantly lower in patients who developed CNS complications than in the non-CNS complication group (55%±9% vs 88%±2%, 29%±11% vs 83%±3%; both P<0.001). The 1-year transplantation-related mortality (TRM) and 2-year TRM were significantly higher in patients who developed CNS complications than those in the non-CNS complication group (45%±9% vs 8%±2%, 58%±11% vs 11%±2%; both P<0.001). The delay or the failure of PLT engraftment and combined with aGVHD are the risk factors for CNS complications. The facts indicate that we should prevent CNS complications when patients who underwent allogeneic HSCT with the delay or the failure of PLT engraftment or aGVHD. Compared with non-CNS complication group, patients who developed CNS complications usually have poor prognosis.